Harvard Astronomy's Supernova Forensics group has teamed up with Astronomy 100 undergraduate students to unveil the nature of the peculiar SN2012au

April 2, 2013

Harvard Astronomy's Supernova Forensics group has teamed up with Astronomy 100 undergraduate students to unveil the nature of the peculiar SN2012au - a massive star that exploded some 75 million years ago. This energetic, slow-evolving and helium-rich explosion provides a golden link between the emerging class of "super-luminous" supernovae and other more seemingly normal supernovae that are far less bright.

Some observations of the supernova were obtained by two generations of Astro 100 students in 2012 and 2013 as part of the department's annual Spring Break trip to Fred Lawrence Whipple Observatory in Arizona. Students were the first to classify the new supernova in 2012 with the FLWO 1.5m telescope within just hours of its discovery by the Catalina Sky Survey. A year later, the next group of students used the FLWO 1.2m telescope to show that SN2012au is still shining bright and thus evolving slowly. A paper led by postdoc, Dan Milisavljevic, has been submitted to the Astrophysical Journal Letters with details on this unusual stellar explosion (link).

"My jaw dropped when I obtained data on SN2012au in December 2012," said Milisavljevic, "and I recognized immediately that something was different about this supernova - something important!" Later careful analysis by the Supernova Forensics group proved Milisavljevic correct as their work on SN2012au led them on the trail of unexpected connections between varieties of supernovae thought to be very different. "It's exciting that the Astro 100 students were among the first on the crime scene," said Dr. Alicia Soderberg, assistant professor in the Harvard Astronomy Department. "In this case, the crime was that a star had exploded with much more energy than usual and showed a number of bizarre properties."

The Supernova Forensics group of graduate students and postdocs led by Soderberg were quick to follow up on the Astro 100 discovery, and initiated a detailed investigation lasting an entire year. Their findings, which challenge previous interpretations of super-luminous supernovae, will prompt theorists and modelers to revisit the nature of these violent explosions, and to come up with new ways to explain how these super-luminous events are connected with lower-luminosity counterparts like SN2012au.